Drautotech

Hello everyone,
i just rebuilt the bottom end ( new pistons, crank, camshaft, bearings etc
-bored .030 oversize
-stock heads with new valve job
-camshaft from comp cams (set up at 0 degrees)
-gross lift .480
- duration@ .050 Intake 210degrees exhaust 220degrees
-all the sensors and gaskets are brand new (just replaced iac sensor and map sensor)
-brand new fuel pump and adjustable fuel regulator set to 45psi
-no vacuum leaks
-new spark plugs and wires with new coil
-ignition based time at 11 degrees advanced
-automatic transmission 700r4
- both pre converters removed along with main converter
-AIR system removed/blocked
- no speedometer or odometer

Issues: The car is stalling on me when i come to a stop or coasting to a stop. Battery voltage drops.
(did not stall on me before engine rebuilt and with no speedometer reading). Does not have the power and acceleration i was hoping for. it also hesitates to accelerate.

I've kind of let this problem get the best of me. I've checked every possible solution people have recommended, did some research myself and I'm at a loss. Its getting to the point where this car is not safe drive and not fun to drive either because it will stall frequently. Please help!!! Has anyone had this similar issues when they rebuild their l98????

My only other option i can think is taking out the computer and changing it from fuel injected to carb. I have a feeling the stock computer isn't compensating for slightly bigger cam and pistons (hypertech chip did nothing). How would i go about doing this?


Any help is much appreciated,
Danny C

jv9999

Have you hooked up something like TunerPro RT to it and watched what's going on in real time? If you haven't, you'd just be guessing. You say it ran OK before without a speedo, but the ECM definitely uses speed as a tuning factor. I would think not having it would cause problems like you describe.

Drautotech

I've tried going to a place to tune it at a local place in my town and they said they dont tune the L98 computers. i could give that a try but i can't have anything like that, just a snap on scan tool to look at data and codes. The speedometer has never worked since i bought the car. I've also been having issues trying to figure out whats the cause of that. Possibly a bad connection to the CCM. I dont think the speedo is the issue here because it has never worked.

aklim

I don't expect the Hyperjunk to do anything other than turn on the fans earlier. You have gotten a small bump in displacement, changed the cam and almost doubled the timing. What makes you think that will run like factory since the spec is now different? I would start by sharing some secrets like your location so someone might be able to direct you to some place that will do dyno tuning and can compensate for your combination.